Walking beam safety switch



June 29, 1965 c. LOWERY WALKING BEAM SAFETY SWITCH Filed April 22, 1963 1 ,uuunu,

III

FIG. 2

"'llll CHARLEY LOWERY INVENTOR- AGENT United States Patent 3,192,336 WALKING BEAM SAFETY SWITCH Charley Lowery, Box 13, Briartown, Okla. Filed Apr. 22, 1963, Ser. No. 274,616 2 Claims. (Cl. 200-61.48)

The present invention relates to oil well pumping equipment and more particularly to a safety-switch for stopping an oil well pumping engine in the event of malfunction of theequipment.

Oil wells produced by pumping means are usually provided with a walking beam which is pivotally mounted intermediate its ends for vertical reciprocation of its respective ends, one end being driven by a pitman and the other end being connected to a rod string for vertical reciprocation of the latter. A common malfunction of this type of pumping equipment is the parting or breaking of the sucker rod string within the well. The weight of the sucker rods and fluid being lifited in the pumping operation is normally off-set by a counter-balance associated with the power means driving the pitman, thus when the rods break the unbalanced weight of the counter-balance often results in damage to the equipment.

It is, therefore, the principal object of the instant invention to provide a safety switch or cut-oil for interrupting the ignition circuit to the pumpingengine and precluding damage being done to the pumping unit components when the sucker rods break or part.

Another object is to provide a device which remains in inactivated position during normal action of the walking beam.

Still another object is to provide a device of this class which may be connected to a walking beam and which will be moved to engine stopping position by a sudden and rapid movement of the walking beam as a result of the parting of the sucker rods.

Yet another object is to provide a device which is simple in construction and efficient in operation and which includes relatively few moving parts which will not easily get out of working order.

The present invention accomplishes these and other objects by providing a pair of eccentrically positioned inertia members normally maintained inoperative by a stop.

Other objects will be apparent from the following description when taken in conjunction with the accompanying single sheet of drawings, wherein:

FIGURE. 1 is a simplified fragmentary side elevational view of a conventional pumping unit installation;

FIGURE 2 is a horizontal cross-sectional view taken substantially along the line 22 of FIG. 1;

[FIGURE 3 is a vertical cross-sectional view taken substantially along the line 3-3 of FIG. '2;

FIGURE 4 is a view similar to FIG. 3 illustrating the manner in which the device is actuated to stop a pumping engine; and,

FIGURE 5 is a fragmentary cross-sectional view illustrating an alternate embodiment of the device.

Like characters of reference designate like parts in those [figures of the drawings in which they occur.

In the drawings:

The reference numeral indicates a conventional pumping unit installed above the surface of the earth indicated by the line 11 and comprising a base .12, an A-frame '14, a walking beam 16, an engine and gear unit 18 and a pitman 20 connecting the pumping unit to one end of the walking beam. The other end portion of the walking beam 16 is provided with .a conventional bridle, not shown, but which is connected to the polished rod 22 which is in turn connected to the sucker rod-s within the well for vertically reciprocating the latter below the tubing head and stufling box indicated by the numeral 24.

3,192,336 Patented June 29, 1965 The above description is conventional and forms no part of the instant invention other than to set forth the components with which the invention is intended 'to be used.

The numeral 30 indicates the device, as a whole, which is rectangular in general configuration and is mounted on the upper surface of the walking beam '16 between the A-frame 1-4 and the pitman connected end of the beam. The device '30 comprises a base 32 and a rectangular cover 84 removably mounted on the base by screws 36. A pair of standards 38 is connected in parallel spacedapart upstanding relation to the base 32 medially its ends. A cylindrical stop 40 is horizontally journal'led between the standards 38 by an axle 42. The stop 40 is provided with a plurality, preferably four, longitudinally extending equally spaced radially projecting lugs 44 for the purposes which will presently be apparent.

A pair of posts 46 is similarly connected to the base at a selected point between the standards 38 and one end of the base. An elongated inertia member or rod 48 is pivotally mounted inter-mediate its ends between the posts 46 by a horizontal pin 50 for vertical reciprocating movement of the ends of the rod 48 under certain conditions as is more fully disclosed hereinbelow. The length of the rod 48 is such that it substantially spans the distance between one end of the base and the stop 40.

The position of the posts 46 is such that the pin 50 is extended through the rod 48 in off-set relation with respect to its medial or central portion and toward the stop 40 so that the mass of the end port-ion 52 of the rod 48 is greater than the mass of its opposite end portion 54 toward the stop 40. Thus the mounting of the rod 48 creates an unbalanced effect of the latter so that the free end of its end portion 54 may be positioned under one of the stop lugs 44 to maintain the rod parallel with respect to the surface of the base 32.

Similarly a second pair of posts 56, connected with the base 62, mounts a second rod 58, in similar ofif-set relation so that its end portion adjacent the stop is positioned in contact with the under surface of a lug 44 opposite the lug engaged with the rod 48.

Electrical contacts 60 and 62 are formed on the depending free end portion of the respective rods 48 and 58. If the members 48 and 58 are formed of electrical conducting material than the contacts 60 and 62 must be insulated from a electrical conducting with the rods in a conventional manner. Cooperating electrical contacts 64 and 66 are positioned on the base 32 in spaced relation below the contacts 60 and 62. Electrical wiring 68, interposed in and forming a part of the ignition of the pumping unit engine or motor 18, is connected to the respective contacts 60 and 64. The contacts 62 and 66 are connected to ground by wires 69.

Operation In operation the device 30 is installed on the Walking beam -16 and positioned as shown by FIG. 3. During normal operation of the pumping unit 10 the walking beam is reciprocated vertically, as shown by solid and dotted lines (FIG. 1) wherein the stop 40 maintains the unbalanced inertia rods 48 and 58 parallel with respect tothe base 32. In the event of a rod break or failure the loss of weight associated with the sucker rod connected end of the walking beam results in an upward and downward jerk or sudden movement of the walking beam ends.

FIGURE 4 illustrates the manner in which the device is actuated by a quick upward movement of the pitman end of the walking beam which results, when the walking beam 16 reaches the limit of the upward movement of its pitman connected end, in an upward movement of the end portion 52 of the inertia rod 48 releasing its end portion 54 from contact with the adjacent lug 44 wherein the unbalanced inertia rod 58 moves its heavier end portion downward to close its contacts 62 and 66 and revolving the stop 40 toward the position shown in FIG. 4 wherein the lugs 44 are rotated out of position for contact by the adjacent ends of the rods 48 and 58. The mass of the end portion 52 of the rod 48 then moves the latter toward its s-olid'line position (FIG. 4) and closes the contacts 60 and 64. Since the wires 68 are interposed in the power unit engine ignition system, closing either set of contacts 62-66 or 6044, grounds the current of the ignition system thus stopping the motor.

The electrical contacts 66-64 and 62-66 :are preferably forrned of non-corrosive conductive material to prevent oxidation and a resulting poor connection when the respective contacts close. Conventional contacts may be used and tipped or coated at their meeting points with a non-corros ive material such as silver.

Alternatively the inertia rods 48 and 58 may be formed Ot non-conductive tubular material, as indicated at 48A (FIG. 5), and provided with a pair of contacts 68A and 64A closed by a quantity of mercury 70 moved to bridge the contacts 60A and 64A by the downward movement of the unbalanced tube end portion 52A.

Obviously the invention is susceptible to some, change or alteration without defeating its practicability, and I therefore do not wish to "be confined to the preferred embodiment shown in the drawings and described herein, further than I am limited by the scope of the appended claims.

I claim:

1. A safety switch for an oscillatory walking beam, comprising: an elongated base; a pair of rod-like inertia members pivotally mounted on said base in longitudinally aligned unbalanced relation; stop means including a cylinder mounted on said base between said inertia members and opposing radial lugs on said cylinder contacting the adjacent end portion of each said member and normally maintaining the latter parallel with respect to said base; and cooperating electrical contacts formed on said base and the end portion of each said inertia member opposite said stop means.

2. A safety switch for an oscillatory Walking beam, comprising: a horizontally disposed rectangular base; u-pstanding supports connected in transversely spaced-apart relation to said base medially its ends; a pair of upstanding transversely spaced-apart posts mounted on said base between said supports and the respective end of said base; an elongated inertia member pivotally supported in unbalanced relation between each said pair of posts for vertical reciprocating movement of its respective end portions; stop means including a cylindrical body mounted between said supports for rotation about a horizontal axis and radial lugs formed on said body and engaged with respective adjacent end portions of said inertia members normally maintaining the latter parallel with respect to said base; and cooperating electrical contacts secured to said base and the respective end of each said inertia member opposite said stop means.

References Cited by the Examiner UNITED STATES PATENTS 2,018,590 10/35 Adams.

2,199,583 5/40 Athy. 2,291,245 7/42 Lorraine '200-6l.52 2,296,053 9/ 42 Porter et a1 ZOO-61.52

ROBERT K. SCHAEFER, Primary Examiner. 

1. A SAFETY SWITCH FOR AN OSCILLATORY WALKING BEAM, COMPRISING: AN ELONGATED BASE; A PAIR OF ROD-LIKE INERTIA MEMBERS PIVOTALLY MOUNTED ON SAID BASE IN LONGITUDINALLY ALIGNED UNBALANCED RELATION; STOP MEANS INCLUDING A CYLINDER MOUNTED ON SAID BASE BETWEEN SAID INERTIA MEMBERS AND OPPOSING RADIAL LUGS ON SAID CYLINDER CONTACTING THE ADJACENT END PORTION OF EACH SAID MEMBER AND NORMALLY MAINTAINING THE LATTER PARALLEL WITH RESPECT 